Danny has a coin collection. 20% of his collection are quarters. If Danny has 13 quarters, how many coins does he have in his collection altogether? A) 26 B) 39 C) 42 D) 65

Answer: Danny had 65 coins altogether in his collection.

Step-by-step explanation:

Let x represent the number of coins that Danny has in his collection.

20% of his collection are quarters. This means that the number of quarters that Danny has in his collection is

20/100 * x = 0.2 * x = 0.2x

If Danny has 13 quarters, it means that

0.2x = 13

Dividing the left hand side and the right hand side of the equation by 0.2, it becomes

0.2x/0.2 = 13/0.2

x = 65